1. Field of the Invention
The present invention relates to electrical cables and, in particular, to ribbon cables of the type in which a plurality of wires ar encapsulated between flexible insulating layers.
2. Description of Related Art
Flat or ribbon cables are useful in a variety of applications in which multiple discrete signals must be carried on separate wires in a restricted space. Because of the number of different signals which may be carried simultaneously by the cable, it is desirable to isolate individual signal wires by placing ground wires between the signal wires. The ground wires prevent electrical fields in the signal wires from inducing undesired electrical currents in neighboring signal wires, the ground wires being connected to a constant potential source, as is well known in the art.
In such cables, a difficulty arises in that the ground and signal wires require separate termination. Generally, in order to terminate or splice the cable, the dielectric material which comprises the insulation for the cable must be removed, after cutting the cable to a desired length, in order to make possible separation of the ground wires from the signal wires. Because the signal and ground wires are packed closely together in a single plane, separation may itself be difficult.
A prior solution to this problem has been to provide a continuous release layer between laminated insulation layers of the cable, thus facilitating peeling apart of the insulation layers. However, wires are still located in a single plane, making sorting and separation of the wires difficult.
Another solution has been to use isolating strips placed at predetermined intervals in the cable to prevent bonding of upper cable and lower cable insulating layers in order to facilitate separation when the cable is cut in those areas. Again, however, the signal wires and ground wires are maintained in the same plane even in the areas where termination is to occur, thus requiring separation of the ground and signal wires prior to termination.